The present invention relates to a method of packaging a chip such as an electronic component on a substrate.
Conventionally, as a means for packaging a chip on a substrate there is known a technique where a mounting head attached to a rotary head to be movable and rotatable picks up a chip from a movable parts feeder to carry and mount the chip toward and on a substrate positioned by an X-Y table assembly. This chip packaging operation is arranged to be effected within a cycle time period. The cycle time period depends upon the operating condition, that is, for example, when the moving distances of the X-Y table assembly and the parts feeder are short, the cycle time period also becomes shorts, and on the other hand, when the moving distances thereof are long, the cycle time period naturally becomes long. Further, in the case of a chip with leads such as QFP, the chip packaging operation takes a longer time as compared with the case of a rectangular chip such as a resistor chip and a capacitor chip because time is taken for detection of a positional deviation of the chip by an optical means. Accordingly, when the cycle time period varies in accordance with the operating condition, the rotational speed of a driving motor for rotating the mounting head is required to be accelerated and decelerated in accordance with the variation of the cycle time period.
On the other hand, for realizing the high-speed packaging of the chip, the cycle time period is preferable to be set to be as short as possible. The shortening of the cycle time period results in the fact that the acceleration and deceleration of the driving motor are performed within the short cycle time period, and hence the driving motor is needed to have a large capacity to allow generation of a large torque. However, there is a limit in the capacity of the driving motor, thereby making it difficult to shorten the cycle time period.